AWWA WQTC58794

Water utilities are facing the challenge of providing higher levels of disinfection while having to lower concentrations of disinfection byproducts. A key factor for meeting these goals is the removal of naturally occurring organic matter (NOM). One alternative that has emerged is a magnetized ion exchange (MIEX) process. It has been demonstrated to be highly effective in removing both low and high molecular weight dissolved organic carbon (DOC) fractions from a range of waters, and works well in conjunction with coagulants for removal of a broad range of organic weight fractions. This process can be applied as a series of mixed contactors to treat raw water ahead of coagulation. The resin is magnetized to facilitate recovery in a settling compartment that is located downstream of the contactors. Most of the recovered resin is returned to the contactors, but a portion is regenerated to provide a steady state condition under which ion exchange capacity can be maintained in the system. A small fraction of fresh resin is added to compensate for any losses. This project provides an evaluation of the performance of the MIEX process under widely different conditions. Effect on removal of NOM and control of disinfection byproduct formation are examined along with assessments of the effects on selected inorganic constituents that include bromide, sulfide, arsenate, arsenite, and perchlorate. Interaction with other plant elements that include disinfection and coagulation-based processes is another critical area that was assessed. Evaluations for this work are a part of an AWWARF study to investigate the effectiveness of the MIEX process in source waters with a wide range of characteristics, such as high DOC - low alkalinity, high DOC - high alkalinity, medium DOC - medium alkalinity, and low DOC - high alkalinity. Bench and pilot scale testing is being conducted at various utilities to provide these assessments. Includes 8 references, table, figures.